Red Fuzz Questions

[oldrocker]

I read some good things about this and was wondering about a couple of things.  First is it possible to use a 741 or 308 in place of the LF351 or was it specifically disigned around it?  Also I read someone had used a BS170 for clipping.  I was wondering how that was done and was it more than one BS170 or in combination with LED's, 1N914's etc...?  Looks like an interesting fuzz pedal.

[newbie builder]

with a lm308 you'd need to add a 30pf cap from pins 1 to 8 i believe, but with a tl071, 741, etc that wouldn't be an issue. i thought that a lf351 sounded better than tl071 (fuller) but i didn't stick in a 741 or 308 yet. i haven't tried a bs170 in there, but i did try an irf520 and it gives a much smoother and more sustainy distortion that is probably good for some lead work. for details on how to do that, you can take a look at the schem for the FKR at beavisaudio.com

[oldrocker]

Thanks.  Yes I knew about the compensation cap on the 308 from the Rat build.  I guess I'll have to breadboard and test out some of these other op amps to see what sounds good.  I will try and check out the Beavis audio site and see what I can find out.  Thanks again.

[HOTGUIT]

the best sound is obtained with 351; you can use as well Tl 061, TL071, TL081 or 741 (single Opamp)
On mine I use a 741 with great results and satisfaction.
I also modded it with a clipping switch that work between 1n914 +1n914/1n914 (asymm. clipping) and two3 mm yellow leds (you can try two red led as well).
If you use mosfets as clippers (IRF 520 suggested) with 1n34A you will'have a very juicy creamy smooth sound.
Anyway it's a very interesting pedal, more like an OD than a Fuzz as the name suggests.

[mac]

I agree this is more OD than Fuzz. Mine has a 351 and a switch to choose Si or Leds. If in doubt, socket the IC and try different ones.
I use it to push the OD channel, like a TS.

mac

[jmusser]

I made this quite awhile back, and it is a very impressive crunchy OD, using some salvaged large red LEDs for clippers. I have no idea why it was called a fuzz.